For coloring and fosterage of highly utilized leather surfaces, like car seats, steering-wheels, motorcyclist's clothes and equipment and the like various compositions and methods of applying such compositions are known:
EP 0 572 353 A1 describes a method of coloring leather with a polyazo dye with at least two sulphur groups and some alkali halogenide.
EP 0 071 420 B2 describes a method of after tanning of leather of oligomers on acryl basis.
EP 0 492 608 A2 describes a process for producing leather comprising the steps of pretreatment, tanning and finishing, the finishing steps including treatment with fatting agent and top finish. A fatting agent for leather is also known from DE-C-22 45 077.
JP 2005 264130 A1 describes a preserving cream for leather without using volatile components or vaseline which is stable for a long period without degradation and applicable to all leather products.
EP 0 927 271 B1 describes a leather-treatment agent which is obtained by polymerization of 70-100 wt.-% acrylic acid and/or methacrylic acid and/or the acid chlorides and/or anhydrides thereof with 0-30 wt.-% of other water-soluble monomers copolymerizable with the first component and 0-20 wt.-% of water insoluble monomers copolymerisable with the two first components. Said polymer being reacted with amines of formula R1—NH—R2, wherein R1 represents a C12-C30 alkyl or alkenyl residue and R2 represents H, a C1-C4 alkyl or C1-C2 hydroxyalkyl residue. Such leather treatment agents are used producing low-fogging leathers, i.e. leathers which do not deliver too much material which may condense on the surface of the window panels of a car, i.e. without making the window panel too foggy.
Chinese Publication 2002-68 31 96 (XP 002143103) proposes a polyurethane leather repairing agent consisting amongst others a distilled water and a thickener being used to simplify leather repair processes.
DE 195 10 242 A1 discloses a leather sheet which is covered on its outer side with a polyurethane containing watery dispersion. This cover layer is prefabricated in a mould with a surface comparable to the original leather. This prefabricated cover layer is used to ennoble a leather sheet by giving the characteristic look of natural leather to the leather sheet.
U.S. Pat. No. 4,507,413 discloses an aqueous polyurethane reactive coating composition suitable for coating leather and other materials and also containing thickeners and pigments.
All said compositions are used for treating the leather surface as a whole.
Leather-surface-repair composition which can be used for repairing damaged spots like scratches, cuts, imperfections and damaged or injured surfaces, is known from U.S. Pat. No. 1,506,983. These compositions substantially consist of carnauba wax, bees wax, shellac wax, dry shellac and turpentine and a color base. This composition is applied to the leather surface by means of a heated spatula or knife blade and subjected to pressure and a rubbing action for working it into a homogenous state.
All patents and publications described above are hereby incorporated by reference into the specification of this application.